Prior art cutting, shaping, and polishing techniques generally fall into three broad categories including guided or unguided cracking, abrasive forming, and localized heating.
Cracking may be done without an external guide, for example by following internal faults or, depending on the material, by following a cleavage plane. Guided cracking may be done in the case of rock by predrilling to create weak spots and then cracking between the drilled holes another example of guided cracking is glass cutting, where a weak line is formed by a glass cutter.
Abrasive forming is perhaps the most commonly used cutting, shaping and polishing technique. Included in this category are sawing, drilling, sanding, grinding, buffing and other techniques which are too numerous to mention.
Localized heating is often used in cutting and shaping metals by melting such as with a torch. Cutting of rock such as granite is also often done this way, by using a flame such as a fuel oil flame to cause individual crystals of rock to thermally expand by amounts which differ from neighboring crystals. This uneven thermal eaxpansion causes small flakes of granite to crack away from the main rock into an airstream which removes the flakes.
Additionally, it is known in the prior art to use solar energy to act as a source of energy for localized heating. However, prior art systems have several drawbacks which have prevented their widespread use.
Small focusing lenses are known to be useful for cutting, melting, and welding jewelry and other articles. Such lenses are usually built into a small frame and are often made from plastic as in the case of small hand-held fresnel type lenses. However, these lenses do not permit an adjustable focal length (the significance of which will be discussed later), nor do they provide for redirecting the solar radiation along a line in the X, Y, and Z planes other than parallel to the incident beam radiation.
Small reflectors or large arrays of reflectors are also widely used to concentrate and redirect solar energy. However, in the known prior art systems, it is impossible for a single operator to both adjust focal length and redirect to varying angles the solar radiation while simultaneously either cutting, shaping, or polishing some material of interest.